Priming and venting arrangement for fuel feed system



April 13, 1965 B. c. PHILLIPS PRIMING AND VENTING ARRANGEMENT FOR FUEL FEED SYSTEM Filed. Aug. 4, 1961 INVENTORZ BERNARD EZPHJLLIPS.

ATTORNEY United States Patent 3 177 920 PRIMING AND VE NTfNG ARRANGEMENT FOR FUEL FEED SYSTEM Bernard C. Phillips, Toledo, Ohio, assignor to The Tiller- This invention relates to a priming and venting arrangement or system for a fuel feed system especially of the character for supplying liquid fuel to aninternal combustion engine and more especially to an arrangement of this character usable with a fuel feed system embodying a diaphragm type carburetor or charge forming apparatus wherein the metering of fuel into the mixing passage of the charge forming apparatus is controlled by aspiration in the mixing passage.

The invention has particular utility with the fuel feed system of internal combustion engines of the character employed for marine or outboard installation of the character wherein priming is usually necessary in order to suc cessfully initiate the operation of the internal combustion engine. Priming devices have been employed with charge forming apparatus of outboard engines particularly of the two cycle type embodying so-called float type carburetors wherein the fuel level in a vented bowl of the carburetor is regulated by a float actuated inlet valve.

With this type of carburetor, a hand operated priming pump of the squeeze bulb type may be successfully employed to elevate fuel from a supply tank disposed at a lower level than the carburetor through a tube into the carburetor and the air purged from the tube through the carburetor bowl as the latter is vented, thus enabling the escape of air entrapped in the fuel supply tube connected with the carburetor. In a diaphragm type carburetor wherein a metering diaphragm controls the flow of fuel into a diaphragm or fuel chamber, the fuel chamber is unvented and it is diflicult or virtually impossible. to prime air locked fuel lines from the supply tank through a fuel pump to the diaphragm carburetor. The fuel pump is usually of the diaphragm type actuated by pulsations from the crankcase of a two cycle engine or other source of varying fluid pressure. In a fuel feed system of thischaracter, the fuel inletva-lve of the carburetor is biased 'to closed position by a spring. If pressure is exerted upon a priming pump sufficient to overcome the spring pressure holding the fuel inlet valve in closed position, the inlet valveris opened and fuel flows through the diaphragm chamber 'directly. into the mixing passage flooding the same so that it is impossible to initiate operation of the engine.

The present invention embraces a method, arrangement or system-particularly usable with a diaphragm type carburetor or charge forming apparatus and a fuel pump wherein a'priming means is associated with a venting means whereby entrapped air in the fuel lines or tubes may readily escape in order to successfully prime the fuel linesto the; carburetor and through the fuel pump to initiate operation of an internal combustion'engine with which the arrangement is associated.

Another object of the invention resides in a priming and venting system for purging fuel conveying means or tubes from a fuel tank to a carburetor wherein the operator is visually informed byflow of fuel out of the venting means that the system has been purged of entrapped air and the system conditioned for engine operation.

Another object of the invention is the provision of a 0f the invention has particular utility in combination of fuel.

Another object of the invention is the provisionof a vent-ing and priming arrangement or system for a fuel feed system and apparatus for an internal combustion engine which is usable with various types of carburetor and fuel pump constructions without modification of these components of the fuel feed system, the arrangement being such that comparatively low pressure upon the priming pump is required to purge iar from the fuel supply to the charge forming apparatus or carburetor for engine operation.

'Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure,

to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a semi-diagrammatic illustration of the priming and venting arrangement or system of the invention associated with a fuel feed pump and charge forming apparatus associated with a two cycle internal combustion engine of the outboard type;

FIGURE 2 is an elevational view of a combined diaphragm type carburetor and pulse operated fuel pump with which the invention has particular utility, portions of the carburetor and fuel pump being shown in cross section for purposes of illustration; 7

FIGURE 3 is a transverse sectional view through the charge forming apparatus or carburetor illustrated in FIGURE 2;

FIGURE 4 is an enlarged sectional view illustrating one form of valved venting means of the invention, and FIGURES is a sectional view illustrating another form of valved venting means of the invention.

While the priming and venting arrangement or system with a fuel feed system embodying a carburetor or charge forming means. of the diaphragm type utilized in con junction with either two cycle or four cycle engines of the outboard marine type, it is to be understood that the priming and venting arangement may be utilized with other types of charge forming apparatus for usewith sta-.

tionary internal combustion engines or other fuel feed a systems where priming means is essential or desirable.

Referring to FIGURE 1 of the drawings, there is illustrated insemi-diagrammatic form the arrangement or system of the invention utilized with -a carburetor or charge forming device of the aspirated diaphragm type and a pulse actuated. fuel pump comprising a fuel delivery systemiordelivering liquid hydrocarbonfuel and air mixture intothe crankcase of an internal combustion i engineof the twoicycle type usable for propelling boats priming and venting system or arrangement for fuel feed 7 where it is c'onventional for the fuel tank or fuel receptacle to. bepositiOnedbeneath or'atra "lower level than the carburetor requiring fuel pumping means to deliver fuel fromthe tank or receptacle'to the carbureton With particular reference to FIGURE 1 the engine illustrated comprises a crankcase 10, a cylinder 12 secured to the crankcase, a crankshaft 16, piston and connecting rod of conventional construction (not shown) being en'- closed within the crankcase and; cylinder, the cylinder. being provided with a spark plug 14 for igniting charge forming mixture the cylinder. The engine crankshaft i6" is equipped with a'flywheel 18, anda starting pulley 2d, the latter adapted to be initially rotated by arstarti'ng cable 22 in the conventional manner.

A hollow strut or tubular enclosure 24 secured to the crankcase projects downwardly and encloses a shaft for transmitting power to a propeller (not shown) at thelower end of the hollow strut 24. A sheet metal enclosure 26 surrounds the crankcase, the cylinder and the flywheel.

as illustrated in FIGURE 1. g

The crankcase 10 is provided with a boss portion 28 adapted to mate with a mounting flange 30 of a diaphragm carburetor or charge forming device or apparatus 32..

The carburetor 32 in FIGURE 1 is the same as that shown in FIGURE 2. However the carburetor 32 shown in FIGURE 2 is provided with a pulse operated fuel pump while the carburetor shown in FIGURE 1 receives liquid fuel from a separate fuel pump 40. The mounting flange 30 is integrally formed with the carburetor body 34 as shown in FIGURE 2, and is secured to the crankcase by suitable bolts (not shown).

In the arrangement shown in FIGURE 1, the fuel pump 49 is secured to the crankcase 10, the pump being of a diaphragm type in which the diaphragm is actuated or vibrated by varying fluid pressure in the crankcase 10 of the two cycle engine in which the fuel and air mixture is pre-compressed in the crankcase prior to its delivery into the combustion chamber of the cylinder. A tube or duct means 42 connects the outlet fitting 41 of the fuel pump with the inlet duct of the carburetor through a T-shaped fitting 43. a

A fuel tank or fuel receptacle 44 disposed below the carburetor 32 is connected to the inlet fitting 47 of the fuel pump 40 by tubular means or tubes 45 and 46 and a priming pump 48 of the flexible squeeze bulb type connected with the tubular mean 45 and 46. The priming pump means 48 is provided with inlet and outlet check valves 50 and 52 of conventional type to promote fluid or liquid flow from the receptacle to the pump 40 thence to the carburetor 32 under conditions hereinafter described. The fuel tank 44 is preferablyprovided with a manually operated vent valve 54 to close the vent in the fuel tank when the engine is not in operation.

The carburetor illustrated in FIGURES 1 through 3, with which the invention has particular utility is of the so-called aspirated type, the body 34 being formed with a mixing passage 56 including an air inlet-58, a Venturi 60 and a mixture outlet 62, the latter registering with a valved passage of conventional construction provided in the boss 28 on the crankcase 10. A shaft 64 journaled' in openings in the body 34 extends across the air inlet 58 and is equipped with a conventional disk-type choke valve 65 for restricting the air inletvduring engine starting operations.

The choke valve is manipulated by an arm 66 secured to the shaft 64. A shaft 68 extends across the mixture outlet passage 62 and is equipped with a disk-typethrottle valve 69 of conventional construction for controlling delivery of fuel and air mixture into the crankcase of the engine. The throttle is operated by an arm (not shown) mounted on the shaft 68. The'charge forming device orcarburetor 32 is provided with a circular wall portion 70 :which forms a seat for a gasket 71, a diaphragm 72 made of flexible imperivous material such as nylon fabric impregnated with a synthetic rubber-like material or resin which is not subject to deterioration by liquid hydrocarbon fuels.

The diaphragm is highly flexible and forms a wall 'of a shallow fuel chamber or diaphragm chamber 74 formed in the body 34. When the carburetor of the character shown in FIGURES 1 through 3 is employed with a separate fuel pump 40 as shown in FIGURE 1', the diaphragm 72. is covered by a closure plate 76 shown in FIGURE 1 which is recessed at the region adjacent the diaphragm to permit flexing movements of the diaphragm 72.

When the: carburetor is used in combination with a fuel pump secured directly to the body 34, the diaphragm 72is secured in place by a disk-like member 78 shown in the diaphragm fuel pump construction. The cover 76 shown in FIGURE 1 is secured to the carburetor body, by suitable screws. The clearance space between the recessed central region of the cover 76 and the diaphragm is vented to the atmosphere through a suitable small opening (not shown) to prevent air lock in the recess.

In the arrangement shown in FIGURE 2 the vent opening for the recessed cover member 78 is illustrated at 80 in FIGURE 3. The diaphragm fuel pump construction, forming a part of the carburetor combination shown in FIGURES 2 and 3, includes a member 82, the members 78 and 82 beingformed respectively with cavities, recesses or chambers 83 and 84, a pumping diaphragm 86 being disposed between the members 78 and 82 and extending across and between the cavities 83 and 84.

The cavity or recess 83 provides with the diaphragm 86 a pumping chamber, the diaphragm being pulse operated by varying fluid pressure, a pulse channel 88 formed in the mounting flange 30 being in communication with the pumping chamber 83 is also in communication with an opening in the cranckcase of the engine registering with the pulse channel. The varying fluid pressure in the crankcase provides the movant for pulsing or vibrating the pumping diaphragm 86 to exert pumping impulses in the fuel chamber 84.

The pump construction illustrated in FIGURE 2 is of the character shown in my Patent No. 2,841,372. The member 82 is provided with inlet and outlet ports, the inlet port being illustrated at 90 in FIGURE 2 which is in communication with a recess 92 formed in the member 82. A filter screen 93 extends across the recess 92 and a closure member 94 is secured to member 82 by means of a screw 95. The member 94 is provided with a recess 96 which receives incoming fuel through a tubular nipple portion 98 and a flexible tube 46, the tube 46 being connected with the priming pump 48 shown in FIGURE 1.

The pumping diaphragm 86 is provided with integral flap valves for cooperation with the inlet and outlet ports formed in the member 82. The outlet port (not shown) is connected by an internal channel or fuel-conveying duct 100 with the inlet 102 formed in the carburetor body 34. A threaded fitting 104 in the carburetor body is provided with a bore in which is disposed a fuel inlet control valve 106, the lower end of which engages or contacts one arm of a lever 108 fulcrumed on a pin in the carburetor body.

I The other arm of the lever engages a member 112 carried by the central region of the fuel metering diaphragm 72 of the carburetor. The valve member 106 has a cone shaped portion which cooperates with an annular valve seat 107 disposed in the inlet passage in the carburetor body. A spring 114. engages the lever 108 to normally bias the valve 106 toward closed position and the end of the lever toward engagement with the member 112 mounted on the fuel metering diaphragm 72.

Under the varying pulsing pressure derived from the crankcase which is communicated to the pumping chamform of valve construction is illustrated in FIGURES 1 and 4. The valve arrangement comprises a T-shaped fittingor member provided with a ,tenon portion 122 which extends through an opening inthe casing or engine. enclosure 26, an abutment 124 engaging the housing to position the fitting with respect thereto.

The tenon portion has a threaded region 126 to receive a securing nut 127, a sealing gasket 128 being disposed between the securing nut and the outer surface of the housing 26, the nut serving to hold the fitting 120 securely to the housing. The fitting 120 is provided with a bore or passage 130 in which is slidably disposed a rod or member 132 of lesser diameter than the passage 130 to faciiitate flow of fuel through the passage 130.

The fitting is provided with a nipple portion 134 which is adapted to receive one end of a fuel conveying tube or tubular means 136, the other end of the tubular means 136 being connected with the T-shaped fitting 43, a stem 138 of the fittting being threaded into a boss 140 formed on the carburetor body when the arrangement shown in FIGURE 1 is employed in association with the fuel pump 40.

When the carburetor-pump combination shown in FIGURE 2 is utilized, the T-shaped fitting 43 is replaced by a threaded plug, and a nipple 116 threaded into a threaded passage formed in a boss 117 on the carburetor body, the passage communicating with the inlet 102. In this arrangement, the fuel from the fuel pump shown in FIGURE 2 is conveyed to the carburetor inlet 102 through the internal passage 100 in communication with the outlet port of the fuel chamber 84 of the pump. The nipple 116 is connected with the vent fittting 120.

A side branch 144 of the fitting 120 is provided with a vent passage or port 146 to which may be secured a vent tube 148 projecting through an opening in the housing 26 to a position illustrated in FIGURE 1 with its outlet 149 visible to the operator. Thus during a priming operation, fuel discharged through the vent outlet 149 indicates to the operator that the fuel feed lines or tubular means have been purged of air and are filled with liquid fuel.

Secured to one end of the rod 132 in the fitting 120 The opposite end of the fitting is provided with a bore 1 154- which accommodates a tenon portion 155 of a manipulating button or member 156 secured upon the end of the rod 132. A sealing gasket 158 surrounding the rod 132 is disposed in the recess 154, a spring 160 positioned between the sealing gasket and the tenon portion of the button 156 normally biasing the valve or obturator 150 toward closed position. i

This is the normal position of the valve during engine operation and prevents flow of fuel through the passage 130 to the outlet or port 146. The valve arrangement is adapted to be opened by the operator exerting pressure upon the button 156 to move the rod 132 and the valve 150 in a right-hand direction, as viewed in FIG- URE 4, which opens or vents'the passage 130 to facilitate flow of entrapped air or volatilized fuel in the fuel line arrangement through the vent or port 146 and through the tube 148.

In initiating starting operations of the engine the operations of venting and priming the fuel conveying lines or tubular mews are as follows:

The operator depresses the button 156 by exerting pressure thereon to move the valve 150 to open position away a I or port 192. The tube 1481s connected to the nipple; 130 and serves the purposes hereinbefore described in and releases pressure'on the button 180.

. t 6 matically by the biasing pressure of the spring 160. Further operation of the priming pump 48 is unnecessary. These operations fill the tubular means 45, 46, 42, the fuel pump and the T-shaped fitting 43 with fuel so. that fuel is at the region of the inlet valve 106 of the carburetor.

The throttle valve 64 is opened, the choke valve 65 is closed, and the engine then cranked by manipulation of the starting cable 22. iReciprocation of the enginepiston sets up reduced pressure in the crankcase 10 effective to cause flow of air through the mixing passage in the car-. rburetor and flow of fuel through a main orifice opening into the mixing passage from the diaphragm fuel chamber 74. The reduced pressure or aspiration in the mixing passage is effective in the chamber 74 to cause upward flexure of the diaphragm 72 whereby the inlet control valve 106 is moved away from its seat and fuel flowed through the inlet passage 102 into the chamber 74 thence into the mixing passage.

The carburetor may be provided with a secondary fuel delivery system including engine idling and low speed orifices (not shown) of conventional construction to facilitate operation of the engine at low or idling speeds. In the arrangement shown in FIGURE 1, the pulse operated diaphragm pump 40 continues to elevate fuel from the fuel receptacle 4 4 and deliver the fuel to the carburetor as long as the engine is in operation.

FIGURE 5 is illustrative of a modified form of valve construction for venting the fuel feed or supply tubes. In this form the fitting 164 is provided with a passage 166 in which is disposed a'longitudinally movable rod 168 equipped at one end with a valve means or obturator 170. The fitting has a shoulder or flange 172 which abuts the housing 26, the threaded tenon portion 174 of the fitting receiving a nut ,176 for securing the fitting to the housing 26.

The fitting is provided with a bore 178 accommodating a tenon portion 179 of a manipulating member or button 180 which is secured to the opposite end of the rod 168. A sealing gasket 182 surrounds the shaft in the bore 178 to prevent flow of liquid fuel along the shaft in the region of the bore 178. An expansive coil spring 184 is disposed between the sealing gasket 182 and the manipulating button 180, the spring normally and automatically biasing the valve into its seat 171'at the entrance of the passage 166.

The fitting 164 is provided with a hollow nipple 18 6 7 providing an inlet passage or port 187 which is adapted to be connected with the tube 136 which is in communication with the fuel inlet region. of the carburetor as hereinbefore described. The fitting 164 is provided with a second hollow nipple portion 190 providing an outlet, vent substantially the same as the operation of the vent valve arrangement shown in .FIGURE4. When it is desired to prime the fuel system by purging air from the fuel lines, the operator depresses the plunger moving the valve member 170 to open position and, while holding the valve in open position, operates the squeeze'member or priming pump 48, which action forces air'in the fuel lines through the inlet or inlet port 187 and past the valve 1'70 along the passage 166 and through the vent or outlet port 192. a

When fuel is delivered from the outlet end 149 of the tube 148, the operator is .visually'informed that the fuel" lines have. beenfilled with liquid fuel and purged of air The expansive pressure of spring 184 automatically closes the ventvalve 170 to prevent any further flow of fuel through the vent or outlet port 192.

If desired, a transparent sight tube may be inserted in the discharge tube 148 in convenient view of the operator and, with such installation, the outlet or vent 149 may be discharged into the tubular strut 24, the fuel supply tank 44 or other region remote from the vent control valve.

Through the arrangement of the invention, the fuel feed system may be readily and quickly primed and as soon as the priming operations are completed, the vent valve member is automatically maintained in closed position under the biasing pressure of the spring means s that during engine operation. no further flow of fuel through the vent means will take place.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

l. A fuel feed system including a charge forming apparatus, a fuel pump arranged to receive liquid fuel from a fuel tank, a manually operable priming pump, tubular means connecting the priming pump with the fuel pump and the supply tank, duct means arranged to con vey liquid fuel from the fuel pump to the charge forming apparatus, venting means including a fitting formed with a vent passage having communication with said duct means, manually operable valve means normally closing the passage, said valve means being movable to a position to vent the passage for purging air from the tubular means and the duct means, and means normally biasing the valve means toward closed position said venting means including means arranged to be visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

2. A fuel feed system including a charge forming apparatus, a fuel pump arranged to receive liquid fuel from a fuel tank, a manually operable priming pump, tubular means connecting the priming pump with the fuel pump and the supply tank, duct means arranged to convey liquid fuel from the fuel pump to the charge forming apparatus, venting meansincluding a fitting formed with a passage having communication with said duct means, manually operable valve meansfor closingthe passage, means biasing the valve means toward closed position, said valve means being movable to an open position to vent the passage for purging air from the tubular means and the duct means venting means including means arranged to be visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

3. A fuel feed system for delivering liquid fuel to a charge forming apparatus including a fuel pump connected with a fuel supply tank, a manually operated priming pump, tubular means connecting the priming pump with the fuel pump and the supply tank, duct means adapted for conveying fuel from the fuel pump to the charge forming apparatus, venting means including a fitting having a passage formed therein for venting the system, said fitting being formed withinlet and outlet ports for said passage, tubular means connecting the inlet port with said duct means, and manually operable valve means obturating said passage movable to a position venting the inlet port to the outlet port, and resilient means normally biasing the valve means topassage obturating position said venting means including means arranged to be visible to the operator Whereby'discharge of fuel through the venting means indicates the com-' pletion of purging of air from the fuel feed system.

4. A fuel feed system for delivering liquid fuel to a charge forming apparatus including a fuel pump connected with a fuel supply tank, a manuallyoperated priming pump, tubular rnnans connecting the priming pump with the fuel pump and the supply tank, duct means adapted for conveying fuel from the fuel pump to the charge forming apparatus, venting means including a fitting having a passage formed therein, inlet and outlet ports of said passage, tubular means connecting the inlet port with said duct means, manually operable valve means for said inlet port movable to a position venting the inlet port to the outlet port, and resilient means normally biasing the valve means to close the inlet port said venting means including means arranged to be visible to the operator whereby discharge of fuel through the ventingmeans indicates the completion of purging of air from the fuel feed system.

5. A fuel feed system for delivering liquid fuel to a charge forming apparatus including a fuel pump connected with a fuel supply tank, a manually operated priming pump, .tubular means connecting the priming pump with the fuel pump and the supply tank, duct means adapted for conveying fuel from the fuel pump to the charge forming apparatus, venting means including a fitting having a' passage formed therein, inlet and outlet ports for said passage, tubular means connecting the inlet port with said duct means, manually operated valve means cooperating with the passage in the fitting for normally closing the inlet port in said fitting, said manually operated valve means being movable to a position venting the inlet port to the outlet port during manual operation of the priming pump to purge said tubular means and duct means of air, said venting means including means arranged to be visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

6. A fuel feed system for an internal combustion engine including a diaphragm carburetor and a fuel pump associated therewith and adapted to receive fuel from a supply tank, a manually operated priming pump, tubular means connecting the priming pump with the supply tank and the fuel pump, duct. means arranged to convey fuel from the fuel pump to the carburetor, venting means including a fitting provided with a vent passage, means establishing communication of said passage with the duct means, and a manually operable valve for the vent passage, a spring biasing the valve toward closed position,

.said valve being movable to a position to-open said vent passage, said venting means including means arranged to be visible to the operator whereby discharge of fuel throughthe venting means indicates the completion of purging of air from the fuel feed system.

7. A fuelfeed system including an aspirated diaphragm carburetor, a fuel pump, a fuel supply tank, a fuel conveying means arranged to connect the tank with the fuel pump and carburetor, a manually operated priming pump interconnected With the fuel conveying means, venting means including a fitting provided with an inlet and outlet anda relatively movable valve member in said fitting,

resilient 'means normally biasing the valve -member to close the inlet, means connecting the inlet of the fitting with a fuel inlet duct of the carburetor, said valve member being arranged to be manually moved to open position during actuation of the priming pump to vent air in said fuel conveying means through the outlet in said fitting, said venting means including means arranged to be-visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

8. A fuel feed system including an aspirated diaphragm carburetor, a fuel pump, a fuel. supply tank, a fuel conveying means arranged to connect the tank with the fuel pump and carburetor, a manually operated priming pump interconnected with the fuel conveying means, venting means including a fitting provided with an inlet and outlet, a relatively movable. valvemember in said fitting, resilient means normally biasing the valve member to closed position, means connecting the inlet of the fitting with a fuel inlet duct of the carburetor, and manually operable means for moving said valve member to open position during actuation of the priming pump to vent air in said fuel conveying means through the outlet in said fitting, said venting means including means arranged to be visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

9. A fuel feed system for an internal combustion engine, said system including a diaphragm carburetor provided with a diaphragm-controlled fuel inlet valve and a fuel pump associated therewith and adapted to receive fuel from a supply tank, a manually operated priming pump, tubular means connecting the priming pump with the supply tank and the fuel pump, duct means connecting the fuel pump with the carburetor, venting means including a fitting provided with a vent passage, means establishing connection of said passage with the duct means, the means connecting the passage and duct means being arranged to bypass the fuel inlet valve, and a manually operable valve for the vent passage, means normally biasing the valve toward closed position, said valve being movable to a position to open the vent passage to purge the tubular means and duct means of air, said venting means including means arranged to be visible to the operator whereby discharge of fuel through the venting means indicates the completion of purging of air from the fuel feed system.

10. A fuel feed system for an internal combustion engine including a diaphragm carburetor provided with a diaphragm-controlled fuel inlet valve and a fuel pump associated therewith and adapted to receive fuel from a supply tank, a manually operated priming pump, tubular means connecting the priming pump with the supply tank and the fuel pump, duct means connecting the fuel pump with the carburetor, a fitting provided with a vent passage, means establishing connection of said passage with the duct means, the means connecting the passage and duct means being arranged to bypass the fuel inlet valve, a manually operable valve for the vent passage, said valve being movable to a position to open the vent to purge the tubular means and duct means of air, and means normally biasing the vent valve toward closed position, the vent 10 being arranged to be visible to the operator whereby discharge of fuel through the vent indicates the completion of purging of air from the fuel feed system.

11. A fuel feed system for an internal combustion engine including a diaphragm carburetor provided with a diaphragm controlled fuel inlet valve and a fuel pump associated therewith and adapted to receive fuel from a supply tank, a manually operated priming pump, tubular me ans connecting the priming pump with the supply tank and the fuel pump, duct means connecting the fuel pump with the carburetor, a fitting provided with a vent passage, means establishing connection of said passage with the duct means, the means connecting the passage and duct means being arranged to bypass the fuel inlet valve, a manually operable valve for the vent passage, a tube connected with the vent passage, said valve being movable to a position to open the vent to purge the tubular means and duct means of air, means normally biasing the vent valve toward closed position, the vent tube being disposed in a position of view ofthe operator whereby discharge of fuel through the vent tube indicates'the completion of purging of air from the fuel feed system.

References Cited by the Examiner UNlTED STATES PATENTS 348,914 9/86 Jackson 251-323 X 1,369,605 2/21 Bellon. 1,867,104 7/32 Scheminger 15846 2,097,492 11/37 Lang 15836.4 2,215,756 9/40 Heinrich et a1. 2,330,558 9/43 Curtis 15836.4 2,414,158 1/47 Mock 15836.4 2,672,189 3/54 Welch 15836.4 2,771,944 11/56 Thomburg 158-38 X 2,795,269 6/57 Witte 158--36.4 X 2,808,102 10/57 Lidecker 158-38 2,818,111 12/57 Ross 15836.4

JAMES W. WESTHAVEH, Primary Examiner.

FREDERICK L. MATTESON, JR., PERCY L. PAT- RICK, Examiners. 

1. A FUEL FEED SYSTEM INCLUDING A CHARGE FORMING APPARATUS, A FUEL PUMP ARRANGED TO RECEIVED LIQUID FUEL FROM A FUEL TANK, A MANUALLY OPERABLE PRIMING PUMP TUBULAR MEANS CONNECTING THE PRIMING PUMP WITH THE FUEL PUMP AND THE SUPPLY TANK, DUCT MEANS ARRANGED TO CONVEY LIQUID FUEL FROM THE FUEL PUMP TO THE CHARGE FORMING APPARATUS, VENTING MEANS INCLUDING A FITTING FORMED WILTH A VENT PASSAGE HAVING COMMUNICATION WITH SAID DUCT MEANS, MANUALLLY OPERABLE VALVE MEANS NORMALLY CLOSING THE PASSAGE, SAID VALVE MEANS BEING MOVABLE TO A POSITION TO VENT THE PASSAGE FOR PURGING AIR FROM THE TUBULAR MEANS AND THE DUCT MEANS, AND MEANS NORMALLY BIASING THE VALVE MEANS TOWARD CLOSED POSITION SAID VENTING MEANS INCLUDING MEANS ARRANGED TO BE VISIBLE TO THE OPERATOR WHEREBY DISCHARGE OF FUEL THROUGH THE VENTING MEANS INDICATES THE COMPLETION OF PURGING OF AIR FROM THE FUEL FEED SYSTEM. 